The present application relates to providing control signals to internal components of hermetic compressors, and more specifically to the controlling of internal components in a hermetic compressor by the use of control signals transmitted on the power lines of the motor of the hermetic compressor.
The operation of hermetic compressors can be controlled through the use of control devices, e.g., solenoids, that are located inside of the housing of the hermetic compressor. By way of example, without limitation, capacity modulation can be controlled in some compressors by a solenoid-actuated valve. Also, an internal bleed valve controlled by an electromagnetic solenoid actuator may be used for pressure equalization on the start-up of the compressor. A controller positioned outside of the hermetic compressor can be used to operate and control the internal control devices of the hermetic compressor.
At least two control wires can be needed to provide actuation control signals from the controller or control panel to a solenoid actuator. To provide the control signals from the controller to the internal control devices of the hermetic compressor, hermetically sealed terminals, one for each control wire, can be used to provide a connection through the housing. The use of the hermetically sealed terminals to provide control signals inside the housing of the hermetic compressor is in addition to the use of a set of hermetically sealed terminals to provide the main supply voltage, e.g., an AC (alternating current) voltage, to the motor inside the housing of the hermetic compressor. The use of additional hermetically sealed terminals for the control wires adds to the manufacturing cost of the compressor, and increases the chances that the hermetic seal of the compressor may be compromised.
Therefore, what is needed is a simple and inexpensive technique to provide control signals to the internal devices in a compressor without the use of dedicated terminals.